The two companies announced a partnership Monday that lets iOS users in the US rack up American Express loyalty points, or spend them, on Uber rides.

Dave Wolf, vice president of global product and business development for American Express, said Amex isn't concerned with Uber's controversy because the company is focused on getting customers want and, apparently, they want Uber. American Express customers spend "hundreds of millions of dollars on Uber," according to Wolf.

"It's where our customers are, it's where our customers are going," he said. "We see them using Uber every day in droves and so it was the most natural fit."

The new integration is another example of how Uber, reportedly valued at $12 billion, has been able to attract powerful partners as its business grows. The on-demand car service that lets people order cars through a mobile app, operates in over 100 cities across the globe with 60 cities in the US. The company paired with a American Express competitor in the past -- online payments leader PayPal. In November, the Bay-owned company chose Uber as its first partner for its mobile payments platform.

When announcing the PayPal partnership, Uber CEO Travis Kalanick spoke highly about PayPal's ability to lead Uber into a global market, particularly in areas where consumers don't favor credit cards. Now, Kalanick told Bloomberg TV, he's "not going to be happy until 100 percent of Uber's users are using AmEx to get around their cities."

To use the new integration, American Express users need to enroll within their Uber accounts. Whenever you request a ride, you can choose to earn doubles points or use points on the ride. In addition to Uber's traditional black car service, you can also activate the loyalty program with Uber's RUSH delivery service, UberX or Uber SUV.

Wolf said this is the first time American Express has had such an integrated loyalty rewards feature in an app. The company has offered similar perks in the past on social media sites like Facebook, Twitter and Foursquare, but only for redeeming offers. Recently, American Express set up a way for people to pay with points for taxis in New York.